 /*******************************************************************************
  * Copyright (c) 2003, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.dialogs;

 import java.util.ArrayList ;

 import org.eclipse.jface.viewers.ITreeContentProvider;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.ui.model.AdaptableList;

 /**
  * Provider used by the NewWizardNewPage.
  *
  * @since 3.0
  */
 public class WizardContentProvider implements ITreeContentProvider {

     private AdaptableList input;

     /*
      * (non-Javadoc)
      *
      * @see org.eclipse.jface.viewers.IContentProvider#dispose()
      */
     public void dispose() {
         input = null;
     }

     /*
      * (non-Javadoc)
      *
      * @see org.eclipse.jface.viewers.ITreeContentProvider#getChildren(java.lang.Object)
      */
     public Object [] getChildren(Object parentElement) {
         if (parentElement instanceof WizardCollectionElement) {
             ArrayList list = new ArrayList ();
             WizardCollectionElement element = (WizardCollectionElement) parentElement;

             Object [] childCollections = element.getChildren();
             for (int i = 0; i < childCollections.length; i++) {
                 handleChild(childCollections[i], list);
             }

             Object [] childWizards = element.getWizards();
             for (int i = 0; i < childWizards.length; i++) {
                 handleChild(childWizards[i], list);
             }

             // flatten lists with only one category
 if (list.size() == 1
                     && list.get(0) instanceof WizardCollectionElement) {
                 return getChildren(list.get(0));
             }

             return list.toArray();
         } else if (parentElement instanceof AdaptableList) {
             AdaptableList aList = (AdaptableList) parentElement;
             Object [] children = aList.getChildren();
             ArrayList list = new ArrayList (children.length);
             for (int i = 0; i < children.length; i++) {
                 handleChild(children[i], list);
             }
             // if there is only one category, return it's children directly (flatten list)
 if (list.size() == 1
                     && list.get(0) instanceof WizardCollectionElement) {
                 return getChildren(list.get(0));
             }
                 
             return list.toArray();
         } else {
             return new Object [0];
         }
     }

     /*
      * (non-Javadoc)
      *
      * @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object)
      */
     public Object [] getElements(Object inputElement) {
         return getChildren(inputElement);
     }

     /*
      * (non-Javadoc)
      *
      * @see org.eclipse.jface.viewers.ITreeContentProvider#getParent(java.lang.Object)
      */
     public Object getParent(Object element) {
         if (element instanceof WizardCollectionElement) {
             Object [] children = input.getChildren();
             for (int i = 0; i < children.length; i++) {
                 if (children[i].equals(element)) {
                     return input;
                 }
             }
             return ((WizardCollectionElement) element).getParent(element);
         }
         return null;
     }

     /**
      * Adds the item to the list, unless it's a collection element without any children.
      *
      * @param element the element to test and add
      * @param list the <code>Collection</code> to add to.
      * @since 3.0
      */
     private void handleChild(Object element, ArrayList list) {
         if (element instanceof WizardCollectionElement) {
             if (hasChildren(element)) {
                 list.add(element);
             }
         } else {
             list.add(element);
         }
     }

     /*
      * (non-Javadoc)
      *
      * @see org.eclipse.jface.viewers.ITreeContentProvider#hasChildren(java.lang.Object)
      */
     public boolean hasChildren(Object element) {
         if (element instanceof WizardCollectionElement) {
             if (getChildren(element).length > 0) {
                 return true;
             }
         }
         return false;
     }

     /*
      * (non-Javadoc)
      *
      * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer,
      * java.lang.Object, java.lang.Object)
      */
     public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
         input = (AdaptableList) newInput;
     }
 }

